Corrosion-resistant fluid heating tank



y 9, 1946. w. H; MARTlN 2,403, 7

coRnosxomRmsxsmm FLUID HEATING TANK Filed May 30, 1944 INVENTOR. WILLIAM H. MARTIN ATTORNEYS Patented July 9, 1946 UNITED STATES PATENT OFFICE CORRO SIGN-RESISTANT FLUID HEATING TANK.

William H. Martin, Lakewood, Ohio, assignor, by mesne assignments, to Republic Industries, Inc., New York, N. Y., a corporation of Delaware Application May 30, 1944, Serial No. 538,000

1 Claim. 1

This invention relates as indicated to corrosion-resistant fluid heating tanks and more especially to tanks such as are used for the purpose of heating and storing hot water as in domestic and commercial establishments.

There has been considerable attention directed to the problem of providing corrosion-resistant linings for tanks of this character. One type of corrosion-resistant lining available is porcelain enamel. This material is of such a nature, however, that when there is a local failure in any portion of the tank, such failure may not be readily repaired necessitating scrapping the entire structure.

A particular problem is presented in the manufacture of tanks of this character when the same are to be provided with an immersion-type electric h'eater which requires that the tank body be provided with some means whereby such immersion heating unit may be removably secured to the tank body by means which Will not leave exposed any surface which will be corroded by the contents of the tank, while, at the same time, providing a structure which can be readily assembled and disassembled without damage to the corrosion-resistant coating on the interior of the tank.

It is a principal object of my invention to provide a structure of the character described which has all of these desirable advantages.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claim, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

Fig. 1 is a fragmentary transverse sectional view of a portion of a tank of the character described showing in detail the features thereof comprising my invention; and

Fig. 2 is an end elevational view taken from the left side of Fig. 1, it being noted that Fig. 1 is taken on a sectional plane substantially indicated by the line l-l in Fig. 2.

Referring now more specifically to the drawing and more especially to Fig. 1, the structure here illustrated comprises a tank body generally indicated at l. The tank with which the invention is associated may be of any general form.

The most common form to which the invention is applied is the conventional cylindrical hot water heating and storage tank sold for domestic use, comprising a cylinder of approximately 1 to 3 feet in diameter, and of various lengths depending upon their capacity. The tank body is in its entirety provided with a coating 2 on the inner surface thereof of a corrosion-resistant material such as porcelain enamel.

The present invention is concerned primarily with the provision of means whereby an immersion heater may be removably attached to the body of the tank with the heating unit thereof extending into the tank space, the entire assembly characterized in that there are no parts exposed to the tank contents which are subject to corrosion. These ends are accomplished by providing an opening in a local area in the tank wall with the wall around such opening preferbly flared outwardly for a slight extent as indicated at 3. A tubular member 4 having an annular skirt 5 is arranged concentrically with the opening in the tank wall and with such skirt in close fitting engagement with the struck-out portions 3 of the tank wall. The parts described are conveniently united by means of a fillet weld 6 such as may be secured either by gas or electric welding operations which are conventional and well-known.

After the parts are thus assembled, the tank, or more particularly, the inner surface thereof is provided with the enamel coating 2 and such coating extends over at least a portion of the axial extent of the inner periphery of the annulus 4. In the preferred embodiment of the invention, the coating 2 extends over the major portion of the inner periphery of the skirt 5.

After the enamel coating has been thus applied by conventional porcelain enamelling procedure, then an insert 1 of corrosion-resistin material is molded in the annular recess provided by the enlarged inside diameter of the skirt portion 5 of the annulus 4. This molding operation may be accomplished by placing a die member in the annulus 4 and then introducing the molding material into the space adapted to re ceive the same and, after the molding material has been permitted to solidify, the die which has close fitting engagement with the inner periphery of the outer portion of the annulus 4 is withdrawn, whereupon the outer portion of the annulus 4 and the axially adjacent portion of the molded insert 6 are provided with a continuous pipe thread.

It will be observed that since the enamel coating 2 extends into the space occupied by the insert 6, the latter will be in overlapping relation with such coating insuring that there are no areas of the metallic wall I exposed to the contents of the tank.

After the parts are assembled and fabricated in the manner described, I then provide a memher 8 which is generally annular in form and which is threaded into the threads formed on the inner periphery of the annulus 4 and molded insert 6. The annulus 8 is provided with a radially extending flange 9 at its outer end. The member 8 is formed of a corrosion-resistant material such as brass, copper, or the like, so as to offer no surfaces to the contents of the tank which may be subject to corrosion thereby.

The immersion heater unit, diagrammatically illustrated as comprising four tubular heating units 10, is carried by a circular plate H likewise formed of corrosion-resistant material such as any of the metals previously mentioned. The heater units I!) may be secured to the plate I I in a variety of ways, none of which form any part of the present invention, excepting that whatever means are employed for that purpose, the materials used should be corrosion-resistant to the contents of the tank, at least those portions which are arranged on the inner face of the plate I l.

The plate II is removably united to the flange 9 of the annulus B by means of a plurality of spaced studs l2.

From the foregoing description, it will be ob served that I have provided a structure in which all of the surfaces exposed to the tank contents are corrosion-resistant. particular advantage of my improved construction is that the supporting means for the immersion unit is of such strength and rigidity and so united to the relatively thin tank wall as not to result in a flexure of the tank wall in local A further and more areas as a result of the normal stresses encountered either in use or incidental to assembly and disassembly of the described combination.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in the following claim or the equivalent of such be employed.

I, therefore, particularly point out and distinctly claim as my invention:

A fluid heating tank provided with a replaceable immersion-type heating element and characterized in that all inner surfaces of the assembly with which the tank contents come into contact are corrosion-resistant, comprising an extension on the outer surface of the wall of said tank about an opening therein, such extension providing a passage with its axis extending at an angle to the plane of the adjacent tank wall, a corrosionresistant coating on the inner surface of said wall and extending outwardly over the inner surface of said passage, an insert of corrosion-resistant material molded in interlocking relation in said passage in overlying relation with said corrosionresistant coating, a thread formed on said molded insert and the axially outer portion of said extension, an annular, exteriorly threaded member of corrosion-resistant material threaded into said passage and provided exteriorly of the tank with a radially extending flange having engagement with the outer end of said extension, an immersion-type heating unit comprising a cover plate of corrosion-resistant material removably secured over the outer end of said passage by attachment to said flange, and a heating element carried.by said plate and extending through said passage into said tank.

WILLIAM H. MARTIN. 

